
18 WESTERN YELLOW PINE IN ARIZONA AND NEW MEXICO. 
before a reproduction cutting is beneficial, but after seedlings have 
come up and before they are firmly established it should be re- 
stricted. 
LIGHTNING. 
As a result of severe thunderstorms in the Southwest during the 
summer months, the damage to yellow pine from lightning is con- 
siderable. Often when a dry tree is struck a ground fire follows. On 
a sample plot of approximately 154 acres, on the Coconino National 
Forest, 1.5 per cent of the stand had been lightning struck. Trees 
are rarely killed outright, but lose a strip of bark from 6 to 10 
inches in width, circling the tree spirally. Occasionally, however, 
trees are killed when struck. Evenif lightning-struck timber remains 
standing, there is considerable loss in quality unless it is logged 
within one or two years. In the latter case the wood is merely blued, 
and can be cut into the lower grades. If, however, the trees are left 
standing for a number of years, lightning scars usually develop into 
serious rot. 
FIRE, 
Because of the open character of the stand and the fire-resisting 
bark, often 3 inches thick, the actual loss in yellow pine by fire is less 
than with other more gregarious species. A crown fire in mature 
timber is almost unheard of, and in a ground fire in the virgin forest 
young saplings often escape complete destruction, though with a fair 
wind and on a steep slope destruction of seedlings and saplings is 
often complete. It is after logging that the damage from fire is 
greatest, on account of the inflammable and unburned slash. The 
butts of mature trees are often fire scarred, but ordinarily this does 
not result in either death or decay. Even in the case of very serious 
scars, the butt log is usually sound, and much of the scar is eliminated 
in the slab. During recent years the yellow-pine type has been 
heavily grazed by sheep and cattle, and in consequence the grass is 
kept short, and the damage from fire very much reduced. 
In June, 1910, a fire occurred on the Gila, Datil, and Apache Na- | | 
tional Forests which burned over about 60 square miles. The area 
burned was steep and rocky, with an unusual quantity of dry forage. 
An investigation showed that the injury to the yellow pine was con- 
fined very largely to the reproduction. On the area as a whole, from 
40 to 50 per cent of the seedlings were killed. The greatest damage © 
was done where the seedlings were in groups, and less where they 
were scattering. Of the saplings on the area, from 23 to 40 per cent 
were killed. While the greatest damage was done in groups, since 
there the fire seemed to burn with the greatest intensity, it was_ 
seldom that all of the trees in any one group were killed. A few 
trees with diameters from 6 to 10 inches, and even up to 20 inches, | 




